Automated pass-through surgical instrument tray reader

ABSTRACT

An apparatus and method for interrogating and automatically identifying a radio-frequency tagged surgical instrument tray and its contents of RFID-tagged surgical instruments are disclosed. The surgical instrument tray and its contents come into contact with an RF signal transmitted by the RFID reader, and as a result, the RFID tags affixed on the instrument tray and the surgical instruments respond by transmitting back to the RFID reader data pertaining to the history of the surgical instruments. A data terminal, which is connected to the RFID reader, may contain data pertaining to the radio frequency tagged surgical instruments during packaging, and during the return of the surgical instrument trays to the packager, identifies the surgical instruments.

This application is a divisional of co-pending U.S. application Ser. No.10/924,897, filed

Aug. 25, 2004, the entire contents of which are hereby incorporated byreference.

FIELD OF THE INVENTION

The invention generally relates to a method and apparatus foridentifying instruments using radio frequency identification (RFID)techniques, and more particularly to a method and apparatus forimplementing a reader for tracking, inspecting and verifying inbound andoutbound surgical instrument trays, kits, and other instruments, tofacilitate tracking and inventory management of surgical instruments andsurgical instrument trays and kits over their useful life cycle.

BACKGROUND OF THE INVENTION

Most of the existing radio frequency readers of RFID-tagged items areemployed in a wide variety of identification systems such as assettracking of goods in department stores, books in libraries, inventorymanagement, asset tracking, matching baggage to passengers in commercialaircrafts, monitoring work in progress, customer identification,delivery control, and delivery of goods such as automatic dispensing ofgasoline at gas stations where a reader interrogates a tag on thevehicle, verifies the data received from the RFID tag, and authorizesthe dispensing of fuel.

Surgical instrument storage and sterilization systems are known. Thesesystems, known as surgical instrument trays or surgical instrument kits,typically consist of metal or plastic trays that hold a variety ofgeneral purpose and/or procedure specific surgical instruments such asforceps, scissors, clamps, retractors, scalpels, etc. These trays arebrought into the operating room (OR) when preparing for surgery, andalso are used as a means to organize, transport and store surgicalinstruments in a medical facility. It is desirable to be able toidentify and inventory the medical surgical instruments to facilitate,repair, and replace them, should they become broken or worn. Trackingand managing surgical instruments used by hospitals is paramount to theefficiency and safety of the use of such surgical instruments, as wellas other hand held medical or surgical instruments.

Due to advances in medical technology that have increased the number ofsurgical instruments now in use and due to the constant pressure in thehealth care industry to reduce operating costs, it has become necessaryto manage and track these instruments more quickly and efficiently. Oneadvancement towards this end has been the creation of surgicalinstrument trays that employ various techniques for controlling thearrangement of instruments on the tray so that any missing instrumentscan be identified quickly. One such method is disclosed in U.S. Pat. No.6,158,437, which uses a combination of instrument identifying indiciaincluding a plurality of graphical indicia that represent an outline ofthe basic shape of each instrument, as well as a terse writtendescription of the instrument to identify the correct placement ofspecific surgical instruments on a tray. Another such method isdisclosed in U.S. Pat. No. 6,4265,041, which utilizes a plurality ofrecessed sections of applicable shape and size distributed on the worksurface of the tray to accommodate specific instruments. Upon extractionfrom the tray, the instruments are in ready position to be relayed tothe person performing the operation. U.S. Pat. Nos. 6,158,437 and6,4265,041 are hereby incorporated by reference in their entireties.Through implementation of the teachings of these patents, a person canvisually inspect a surgical instrument tray and make a determination asto whether any instruments are missing or misplaced.

Another function provided by surgical trays is to facilitate groupsterilization. Sterilization is of paramount importance in a surgicalsetting such as a hospital to prevent potentially deadly infections topatients undergoing surgery. Prior to every surgical procedure, allsurgical instruments and trays must be sterilized. Also, following eachsurgical procedure, all instruments on a given tray, if not wrappedseparately, whether soiled or not, must be re-sterilized beforesubsequent usage. In order to increase the speed and efficiency ofsterilization, entire surgical trays containing several instrumentsoften are placed in a sterilization chamber at once. The sterilizationchamber may provide any combination of heat, pressure, and/or fluid orvaporous sterilant to the trays and all the instruments containedtherein. Sterilization techniques are ubiquitously well known in theart. Thus, a detailed discussion of them has been intentionally omitted.

Over time, and through ordinary usage, as well as due to thesterilization process, surgical instruments suffer wear and tear andeventually reach the end of their life cycle. Thus, it has becomenecessary to periodically inspect and maintain records on usage ofsurgical instruments so that they can be replaced as necessary. Also,due to the fact that they are constantly moved from the operating roomto sterilization, to storage, and back to the operating room, variousinstruments on a given tray may become lost. Because certain instrumentsare so specialized that there are no functional substitutes, it also hasbecome necessary to regularly inspect trays for any missing instrumentsand to readily identify specific instruments that are missing. Existingmethods for performing these necessary functions are overly reliant oncostly human interpretation. Also, in some cases, a skilled technicianmay be required to identify missing instruments.

Several methods currently exist for tracking and providing informationabout items that may be useful for tracking surgical instruments andtrays. For example, in retail and manufacturing applications, inventoryitems typically carry printed labels providing information such asserial numbers, price, weight, manufacturing or use dates, and size.Usually, these labels are not machine readable, but rather require humaninterpretation. Another method for tracking and providing informationabout items that ameliorates some of the short comings of printed labelsis bar code labeling. Bar code labels are characterized by a pattern ofvertically oriented machine readable variable width bars that, whenilluminated with a bar code scanner, create a reflection pattern thattranslates into a unique series of numbers. The series of numbers mustthen be correlated to product descriptions in a relational database incommunication with the bar code scanner for purposes of identification,price checking, and inventory management.

Bar code labels have received widespread use from product tracking inthe package delivery business, to physical inventory tracking and evenpoint-of-sale terminals. In some respects, due to their machine readablenature, bar code labels represent a significant improvement over printedlabels. Also, they are relatively cheap and easy to generate with aprinter. There are some limitations to bar codes, however, that limittheir application to surgical instruments and trays. Bar codes arelimited in size by resolution limitations of bar code scanners, and theamount of information that the symbols can contain is limited by thephysical space constraints of the label. Therefore, some objects may beunable to accommodate bar code labels because of their size and physicalconfiguration. In the field of surgical instruments, this may precludebar code labels from some smaller or non-geometrically shapedinstruments. In addition, labels only store a number that is meaninglessuntil associated with a database.

Another limitation of bar code readers is that they require line ofsight in order to read the reflection pattern from a bar code. Oneproblem is that as labels become worn or damaged, they can no longer beread with the bar code scanner. This is particularly likely in the fieldof surgical instrument trays because of the harsh conditions the labelsmust undergo during sterilization. Also, because a person operating thebar code scanner must physically orient either the scanner or theproduct to achieve line of sight on each item being scanned, items mustbe scanned one at a time resulting in prolonged scan time. In addition,because bar code scanning requires the operator to handle eachinstrument in order to scan it, a potential safety problem is created.Soiled instruments pose a biohazard because they may have come incontact with bodily fluids, and often have sharp edges. After theinstruments have been sterilized, they should not be touched again untilsurgery to prevent contamination. Therefore, direct human contact eitherpre or post sterilization may be problematic. Another limitation of barcode labels is that they are static. Updating the information in thesemachine-readable symbols typically requires printing a new label toreplace the old.

Data carriers such as memory devices provide an alternative method fortracking and providing information about items. Memory devices permitlinking of large amounts of data with an object or item. Memory devicestypically include a memory and logic in the form of an integratedcircuit (“IC”) and a mechanism for transmitting data to and/or from theproduct or item attached to the memory device. A promising memorydevice-based product identification technology that ameliorates many ofthe above noted deficiencies of both printed labels and bar coded labelsis that of radio frequency identification (RFID) technology. RFIDsystems use an RF field generator and a plurality of RFID tags attachedto goods and products to store and retrieve information about the goodsand products. RFID tags are miniature electronic circuits that storeidentification information about the products they are attached to. AnRFID tag typically includes a memory for storing data, an antenna, an RFtransmitter, and/or an RF receiver to transmit data, and logic forcontrolling the various components of the memory device. The basicstructure and operation of RFID tags can be found in, for example, U.S.Pat. Nos. 4,075,632, 4,360,801, 4,390,880, 4,739,328 and 5,030,807, thedisclosures of which are hereby incorporated by reference in theirentirety.

RFID tags generally are formed on a substrate and can include, forexample, analog RF circuits and digital logic and memory circuits. TheRFID tags also can include a number of discrete components, such ascapacitors, transistors, and diodes. The RF transmission of data can beaccomplished with modulated back scatter as well as modulation of anactive RF transmitter. These RFID tags typically come in one of twotypes: active or passive. Active tags are characterized in that theyhave their own power source, such as a battery. When they enter an RFfield they are turned on and then emit a signal containing their storedinformation. Passive tags do not contain a discrete power source.Rather, they become inductively charged when they enter an RF field.Once the RF field has activated the passive circuit, they emit a signalcontaining their stored information. Passive RFID tags usually includean analog circuit that detects and decodes the interrogating RF signaland that provides power from the RF field to a digital circuit in thetag. The digital circuit generally executes all of the data functions ofthe RFID tag, such as retrieving stored data from memory and causing theanalog circuit to modulate to the RF signal to transmit the retrieveddata. In addition to retrieving and transmitting data previously storedin the memory, both passive and active dynamic RFID tags can permit newor additional information to be stored in the RFID tag's memory, or canpermit the RFID tag to manipulate data or perform some additionalfunctions.

An advantage of RFID tags over other machine readable ID tags such asbar code tags is that they do not require line of sight to be read by anRFID reader. Because RF waves can penetrate surfaces impervious to lightwaves, the tags can be encapsulated into ruggedized containers.Furthermore, a group of tags placed within the influence of an RFIDreader can be read in batch mode. Also, in the cases of dynamic RFIDtags, information stored in the tags can be updated allowing them toserve as transactional records.

Due in part to a relative increase in cost over equivalent barcode-based systems, RFID tags were originally used only on items ofsufficiently high value to justify their use or in environments wherebar coding was not possible such as anti theft protection. However, withthe price of RFID tags now reaching as low as 5 cents per tag, andbecause of reductions in size due to an overall trend towardsminiaturization in circuit designs, they are being applied to many typesof products, both at the consumer level as well as in manufacturingprocesses. RFID tags provide a robust yet cost effective solution toinventory tracking and management.

Other methods of tracking inventory employ color-coding techniques toidentify different surgical instruments. Others optically mark eachsurgical instrument, and later scan the surgical instruments with ahand-held scanner which is connected to a data terminal to ascertain thehistory of that surgical instrument. These methods require the surgicalinstrument to be removed from the tray on arrival, and scanned byhumans—a method that is costly and time-consuming.

The description herein of various advantages and disadvantagesassociated with known apparatus, methods, and materials is not intendedto limit the scope of the invention to their exclusion. Indeed, variousembodiments of the invention may include one or more of the knownapparatus, methods, and materials without suffering from theirdisadvantages.

SUMMARY OF THE INVENTION

There is a need in the art for inventory systems that include a moreefficient method and apparatus for acquiring historical data of surgicalinstruments with speed and efficiency. There also is a need to develop amethod and apparatus for acquiring information about surgicalinstruments that reduces handling costs, automates the verificationprocess, and overcomes some or all of the aforementioned problems.

Embodiments of features of the invention include a method and apparatusfor automatically and wirelessly inventorying surgical instruments andthe like, by retrieving information indicative of the manufacturer, partnumber, serial number and manufacturing data, usage and maintenancehistory of each surgical instrument. The method and apparatus allow forlower handling costs of surgical instruments, increase the accuracy ofthe verification process of data pertaining to each surgical instrumentwith a reduction of human contact, and include a real-time datacollection resulting in rapid data acquisition, and increased speed ofinventory updating of such surgical instruments.

According to a feature of an embodiment of the invention, a radiofrequency identification (RFID) reader device is implemented tointerrogate a smart surgical instrument tray with a number of surgicalinstruments that are tagged with a radio frequency identificationread/write tags that identify each surgical instrument in terms ofmanufacturer, part number, name, usage, maintenance history, among otherpieces of useful information. In a preferred embodiment, the surgicalinstrument tray arrives at a distribution center, preferably via aconveyer belt on which the RFID reader of the invention is mounted. Asthe surgical instrument tray is presented into a wireless radiofrequency field of the RFID reader device, an interrogation signal isemitted that activates the RFID tags that are placed on the surgicalinstruments, and enables a response by the RFID tags via atransceiver/antenna combination. The transceivers along with the antennacollect data from the RFID tagged surgical instruments and passes thedata in a wireless or wired fashion to a data output device, such as adesk top PC.

In a preferred embodiment of the present invention, the reader devicecomprises a power coil that generates power required to power up theradio frequency tags, an antenna connected to a transceiver of thereader device for transmitting interrogation signals, and receiving datasignals back from the RFID tags.

Another feature of an embodiment of the invention includes a method andapparatus for identifying surgical instruments in an surgical instrumenttray. In this embodiment, outbound surgical instrument trays arepackaged together with read/write tags in a warehouse, and inboundsurgical instrument trays arriving from customers are received andprocessed. In a typical embodiment of the invention, a reader device ismounted on a conveyer belt mechanism, or other means for transportingsurgical trays, and connected to a host data terminal, preferably adesk-top personal computer. One aspect of the invention provides a smartsurgical instrument tray, with its contents of RFID tagged surgicalinstruments arriving at a central distribution center. The surgicalinstrument tray is placed on a conveying apparatus, and when thesurgical instrument tray reaches a capture zone of reader, the devicereader transmits an interrogation signal. In response to theinterrogation signal, a transceiver/antenna combination that isincorporated into the surgical instrument tray interrogates the RFIDtagged individual surgical instruments, receives a data signal back, andin-turn transfers the data to the reader device. The data then aretransferred to a data terminal, or the like, in order to compare thedata to a database pertaining to the history of each individual surgicalinstrument.

Another feature of an embodiment of the invention provides auser-interface application system for facilitating a program thatidentifies smart trays, and RFID tags that are associated with differentsurgical instruments. During the creation of a surgical instrument trayand associated RFID-tagged surgical instruments, a user may activate a“Create Tray” field, “Create Instrument” field, and “Associate” fieldthat populates a database on a host data input/output terminal withidentification of a tray, the RFID-tagged surgical instruments containedin the tray, and data that associates those tags with a specific tray.On arrival of the surgical instrument trays in the distributionfacility, a user may activate a “Verify Tray” field to accurately verifytrays and associated surgical instruments, and to check for accuracy ofthe surgical instrument tray and its contents.

Other aspects and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The purpose and advantages of the present invention will be apparent tothose of ordinary skill in the art from the following detaileddescription in conjunction with the appended drawings in which likereference characters are used to indicate like elements, and in which:

FIG. 1 is a schematic diagram of a radio frequency reader according toan embodiment of the present invention;

FIG. 2 is a schematic diagram illustration of a wireless radio frequencyreader according to an embodiment of the present invention;

FIG. 3 is an exemplary screen display of the user selection illustratingthe tracking of surgical instrument trays according to an embodiment ofthe present invention;

FIG. 4 is an exemplary screen display of the user selection illustratingan surgical instrument tray data table according to an embodiment of thepresent invention;

FIG. 5 is an exemplary screen display of the user selection illustratingthe creation of surgical instrument trays according to an embodiment ofthe present invention; and

FIG. 6 is an exemplary screen display of the user selection illustratingthe tracking of surgical instrument trays, surgical instruments andhistory according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is intended to convey a thorough understandingof the invention by providing a number of specific embodiments anddetails involving automating and adding value to surgical instruments,and surgical instrument kits. It is understood, however, that theinvention is not limited to these specific embodiments and details,which are exemplary only. It is further understood that one possessingordinary skill in the art, in light of known systems and methods, wouldappreciate the use of the invention for its intended purposes andbenefits in any number of alternative embodiments, depending uponspecific design and other needs.

Preferred embodiments of the present invention include a method andapparatus for automatically and wirelessly inventorying surgicalinstruments and the like, by retrieving information indicative of themanufacturer, part number, serial number and manufacturing data,cleaning date of each surgical instrument, when the process wascompleted, etc., and displaying such information on a data outputequipment such as a computer. The invention is not limited to the typesof information that can be retrieved from the surgical instrument, andskilled artisans will appreciate the various types of useful informationthat are desirable for each specific instrument. Embodiments of themethod and apparatus allow for lower handling costs of surgicalinstruments, increased accuracy of the verification process of datapertaining to each surgical instrument with a reduction of humancontact, and real-time data collection resulting in fast dataacquisition that speeds up the inventory updating of such surgicalinstruments.

Embodiments of the present invention avoid the problems associated withhuman interaction by implementing an RFID reader that wirelesslyacquires data pertaining to each surgical instrument tray and itscontents. RFID is a technology that incorporates the use ofelectromagnetic or electrostatic coupling in the radio frequency (RF)portion of the electromagnetic spectrum to uniquely identify an object,animal, or person. RFID is coming into increasing use in industry as analternative to the bar code. The advantage of REED is that it does notrequire direct contact or line-of-sight scanning. An RFID systemtypically consists of three components: an antenna; a transceiver (oftencombined with the antenna into one reader); and a transponder (the RFtag) electronically programmed with certain unique information. Theantenna emits radio frequency waves to activate the transponder (tag) inorder to read or write data to it. In turn, the tag transmits data backto the antenna, data used to interface with a database to carry out afunction such as inventory processing.

Referring to FIG. 1, a radio frequency identification (RFID) reader 100is illustrated in accordance with one embodiment of the invention. Theradio frequency identification (RFID) reader 100 includes sidestructural members 105, 120 and a top member 110 that reflectelectromagnetic waves as a housing for a radio frequency reader situatedon a conveyor belt 150. Preferably, these members are made from a metalor other material having structural integrity and capable of reflectingelectromagnetic waves. A threaded hole 130 preferably is positioned onone of the side members 105 or 120, to facilitate a cable connection 125to a data terminal (not shown). An RFID reader module 115, preferablyattached to the inside portion of the top member 110, emits a radiofrequency signal 140 for interrogating a surgical instrument tray or kit145, along with the contents of the tray or kit 145, which may includeRFID-tagged surgical instruments. It is preferred that the surgicalinstrument tray or kit 145 passes through a cavity or other aperture 135created by the structural members of the radio frequency reader 100.

One aspect of this embodiment provides a method whereby: (i) a surgicalinstrument tray 145, containing a plurality of surgical instrumentstagged with read/write RFID tags, arrives at a central distributioncenter; (ii) an RFID reader 100, positioned on a conveying mechanism150, preferably a conveyor belt 150, transmits an interrogation signal140; (iii) in response to the interrogation signal, atransceiver/antenna combination, which preferably is incorporated intothe surgical instrument tray 145 and/or on the plurality of RFID taggedsurgical instruments, interrogates the RFID tagged components andreceives a data signal back; (iv) the transceiver/antenna combinationtransfers the data to the RFID reader module 115; and (v) the data istransferred to a data terminal via a cable 125 that passes through anopening 130 on the side member 120 of the RFID reader. The data terminalcompares the data to information pertaining to the history of eachcomponent. Typically, the RFID reader is part of a wirelesscommunication system that includes one more transponders in the form ofRFID tags, affixed on surgical instruments to enable the identity ofeach surgical instrument to be remotely and accurately inspected andverified, as well as each surgical instrument's history of usage, repairand age determined.

In accordance with this embodiment, the RFID reader 100 preferably iseither permanently, or temporarily fixed or anchored to the conveyingmechanism 150. The instrument tray or kit 145 also preferably includes aplurality of instruments, preferably surgical instruments, that each areindividually tagged with an RFID tag. In addition, the cable 125 maypass through opening 130 in any of the members 105, 110, 120, or nocable 125 is employed. In the case of no cable 125, the RFID readermodule 115 is capable of wirelessly transmitting data to a data terminalusing wireless data transmission techniques well known in the art.

According to an additional preferred embodiment of the presentinvention, and in reference to FIG. 2, the radio frequencyidentification reader 210 include a transceiver 215 capable ofcontinuously transmitting an interrogation signal 255, in the form of anRF carrier sine wave. The transceiver 215 also is capable ofcontinuously receiving data signals 265, and includes an antenna 220 fortransmitting and receiving signals to and from an RFID tagged surgicalinstrument 250. While the transceiver 215 is capable of continuouslytransmitting and receiving various signals, skilled artisans willappreciate that the signals need not be continuous, but rather may beinitiated by an event, such as the approach of an instrument tray or kit145 (FIG. 1).

The RFID tag 250 that is affixed to a surgical instrument or othercomponent preferably includes a combined receiving and transmittingantenna/coil 245, preferably a patch antenna for receiving the RFcarrier signal 255, and a transceiver 240, which can contain one or moreamplifiers, key means, sawtooth pulse generator, a frequency converter,and electronically programmable integrated circuit memory (not shown)for holding data. The integrated circuit memory may be a random accessmemory (RAM) a memory unit.

The RFID tag being a passive tag can be powered by a rectified ACvoltage generated across the antenna coil 245 by the RF field generatedby the RFID reader 210. The tag preferably is adapted to deliver storedinformation to data terminal 260 after modulating the RF carriertransmitted by the RFID reader 210. The storing of information in thememory of the RFID tag can be accomplished in accordance with theprocedures set forth in U.S. Pat. No. 4,390,880, the disclosure of whichis incorporated by reference herein in its entirety.

For example, a signal 255 (FIG. 2) that is coded, preferably is emittedfrom reader 210 to the RFID tag transceiver 240. The signal 255 mayinclude a key signal component, which typically is of such a nature thatit corresponds to a pre-selected key code and it actuates a key meansthat is preferably included in the transceiver 240. The key signalcomponent in turn preferably places the memory in condition for storingcoded binary information contained in signal 255 in the form of a pulsetrain.

More specifically, the RFID reader 210 preferably continuously generatesa magnetic alternating field in the radio frequency range, called acarrier signal 255, which activates RFID tag 250 affixed on the surgicalinstrument or other component when the signal passes through the antennacoil 245. This generates a rectified AC voltage for powering the RFIDtag. The activated RFID tag accesses its internal data and sequentiallyvaries the electrical loading of its coil causing slight fluctuation inthe RFID reader's carrier signal amplitude, thereby modulating theamount of power drawn by the RFID tag from the reader field. The RFIDreader 210 senses the variations in field power consumptioncorresponding to the data in the RFID tag, and then decodes and outputsthe data, which in turn is transmitted to the data terminal 260. Thisparticular method is known in the art as backscatter modulation. Becausethere may be more than one RFID-tagged surgical instrument in thesurgical instrument tray, multiple RFID tags may be read by the readersimultaneously. In order to avoid data corruption due to a number ofRFID tags transmitting at the same time, an anti-collision protocol isimplemented.

The received, modulated carrier wave 265 at antenna 220 preferably isfed to an envelope detector or the like (which may be a simplerectifying diode) where it is detected (demodulated) to recover orretrieve the modulating signal. The transmitted signal may be made up oftwo separate signals or signal components that are transmitted one afterthe other: one being the above-mentioned key signal component; and theother being the information bearing signal component. It is understoodthat even though the information bearing signal and the key signal arereferred to as components of a signal, they are not necessarilymodulated onto the radio wave simultaneously, but instead can betransmitted one after another. The key signal component usuallyimmediately precedes the information-bearing signal component in thesignal. Each of the key and information-bearing signal components in thesignal preferably is advantageously a binary coded digital signal in theform of a pulse train.

Following detection at the transceiver 215, the signal received by thereader device 210 is fed to an amplifier circuit that amplifies thesignal. The reader device 210 also preferably includes a decodingmechanism for decoding the coded information in signal. The key meanspreferably is connected to the output of amplifier circuit to receivethe key signal component in signal. The key means can compare thereceived key signal with a key code that is stored in the key means, andif the received key signal corresponds to the stored key code, the keymeans operates to feed a write signal to the memory via a conductor orthe like. The reader device 210 also preferably includes a voltagecontrolled oscillator that provides an oscillating output signalfrequency, a mixer for downconverting the received signal, one or morebandpass filters, one or more amplifiers, and a demodulator. The writesignal preferably places the memory in its write mode and hence in acondition to store incoming data or information. The information-bearingsignal or signal component of signal 265 then preferably is fed via aconductor or the like to the data input of the memory and is stored inmemory if the received key signal component conforms to the stored keycode to cause the generation of the write signal.

The key signal mentioned above preferably is of such a nature to keepreflections from an emitted signal or a signal emitted from an unknowntransmitter from placing the memory in its write mode. In this manner,the operation of the key means with the key signal has the effect ofavoiding or reducing the chance of storing undesired information in thememory. After storing the information, the key means removes the writesignal from the memory so that the memory is rendered incapable, ofstoring undesirable information. The pulse amplifier (if present), keymeans and memory are of suitable, known types, and any of the knowntypes or later discovered types can be used in the present invention.The memory capacity in the memory may be, for example, 64 bits orhigher. A voltage source, for example a battery with long service life,preferably powers the memory unit so that the information fed into thememory is retained. The data speed of the memory is designed to besufficient to transfer code depending on the relative speed between thetransceiver 215 and the data terminal 260. Those skilled in the art arecapable of designing the data speed of the memory depending on thedesired relative speeds, using the guidelines provided herein.

An additional embodiment of the invention is illustrated in FIG. 3,which is an exemplary screen display associated with a data terminal foridentifying and inventorying surgical instruments used in surgicalprocedures. As shown in FIG. 3, a screen display 310 preferably runs ona custom application program, (although standard application programsalso could be used), and comprises a number of fields anduser-executable functions. In a preferred embodiment of the presentinvention, RFID-tagged surgical instruments are packed into individualtrays, and before creating an instance of a tray in the database, a usercreates an instance of all the RFID-tagged surgical instruments that oneparticular tray may hold. For example, the user may enter a name for asurgical instrument in the “Instrument Name Field” field 320, and theRFID tag associated with a specific surgical instrument in the “TagRFID”field 330. The user then may activate the “Create Instrument” field335, where the application program searches for prior instances of thesurgical instrument by checking the entered name or the RFID tagassociated with the surgical instrument. The user then is prompted toenter more information, such as the cleaning and sterilizing date ofeach surgical instrument, whether the process was completed, and otherremarks about the instrument. Once the application program verifies thatno instances of the surgical instrument exists in the database, theprocess then moves onto creating the tray in which the RFID-taggedsurgical instruments is packaged in.

In a similar fashion, to create an instance of a tray in the database, auser enters a name of a tray in the “Tray Name” field 325, and thenactivates the “Create Tray” function 315, thereby triggering a databasesearch for any prior instances of the named tray. Once the search iscompleted, and no prior instances of the of the tray are found, thenamed surgical instrument in the “Instrument Name” field and theassociated RFID tag in the “Tag RFID” field is associated with the trayby activating the “Associate” field 340. Afterwards, the nextRFID-tagged surgical instrument is processed and associated with thetray, until the required number of surgical instruments are packaged.The instrument trays, referred to know as “smart” instrument trays, thenare shipped back to surgical instrument suppliers, and after their usein surgical operations by hospital personnel, these trays typically arereturned to at a distribution center. When a “smart” surgical instrumenttray arrives, it can be placed on a conveying mechanism (e.g., aconveyor belt) to pass through a RFID reader of the present invention.The RFID-tagged instruments receive an interrogation signal from theRFID reader, that in turn receives data back, and the received data istransferred to a data terminal.

In an embodiment of the present invention, and in reference to FIG. 3,there is provided a method for verifying the identification of returnedsurgical instrument trays, and associated surgical instruments. Theexemplary screen display of FIG. 3 facilitates a user to run averification method. On data acquisition from the RFID reader, the useractivates the “Verify Tray” field 350 of the screen display associatedwith a data terminal, which initiates an operation for validating thesurgical instrument tray as well as the its contents of RFID-taggedinstrument trays against a database containing previously instantiatedsurgical instrument trays. In response to the activation, the “ExpectedInstruments” field 360 and the “Expected RFIDs” field 370 are populatedwith information from the database, while the “Actual Instruments” field380, and the “Tag RFIDs Read” field 390 are populated with the data readfrom the smart instrument tray. For faster processing, when there is amatch between the data read by the RFID reader and the information inthe database, the background of the list in the “Expected Instruments”field 360 turns green for quick visual recognition by the user. In theevent that there is a mismatch between the data read by the RFID readerand the information in the database, and there are instruments missing,the “Missing Instrument” field will be populated with a list of themissing instruments, with a red color background to signify an errorcondition. When the comparison shows more instruments than expected, the“Extra Instruments/Tags” field is populated with a list of the excessiveinstruments and associated RFID tags, also with a red color background.Skilled artisans will appreciate that any background color can be used,or no background color at all.

FIGS. 4-6 are various screen displays that could be present using themethods described above with reference to FIG. 3. FIG. 4 depicts ascreen display of a surgical instrument tray data table that identifiesthe instrument tray and its RFID tag number, indicates the number ofcomponents (e.g., count 7), and displays when created and last modified.FIG. 5 is a screen display of a particular component in a surgicalinstrument tray. The display reveals information regarding thecomponent, in this case a bone saw handle, its RFID tag number, the trayit belongs in (and the tray RFID number), as well as when the data wascreated and last modified. FIG. 6 is a screen display of a table of avariety of surgical instruments, such as all of the instruments taggedby a particular manufacturer. The table can be used to track surgicalinstrument trays, components of the tray, surgical instruments, and thehistory of the trays and instruments.

While the foregoing description includes many details and specificities,it is to be understood that these have been included for purposes ofexplanation only, and are not to be interpreted as limitations of thepresent invention. Many modifications to the embodiments described abovecan be made without departing from the spirit and scope of theinvention.

1. A method for verifying contents of a surgical instrument tray,comprising: moving the tray into a wireless radio frequency (RF) fieldof an RF reader, the tray provided with an RFID tag, the tray furtherincluding a plurality of surgical instruments each tagged with an RFIDtag, the surgical instrument RFID tag including instrument data relatedto the respective surgical instrument, and the tray RFID tag includesdata related to the respective surgical instruments contained therein;receiving at the RF reader an RF signal containing the instrument datafrom the tagged surgical instruments and an RF signal containing thetray data from the tagged tray to provide read instrument data;transferring the read instrument data to a terminal connected to the RFreader; comparing the read instrument data to a database that includespredetermined tray data and surgical instrument data to assess whetherthe contents of the tray from the read instrument data match thepredetermined surgical instrument data in the database; and displayingthe read instrument data and the predetermined surgical instrument data.2. The method of claim 1, further comprising: detecting a mismatchbetween the read instrument data and the predetermined surgicalinstrument data.
 3. The method of claim 1, further comprising: detectinga missing instrument based on comparing the read instrument data and thepredetermined surgical instrument data.
 4. The method of claim 1,further comprising: detecting an extra instrument based on comparing theread instrument data and the predetermined surgical instrument data. 5.The method of claim 1, wherein the predetermined surgical instrumentdata includes usages, age, and repair information for the plurality oftagged surgical instruments.